Risk of contracting pneumonia among patients with predialysis chronic kidney disease: a population-based cohort study in Taiwan

OBJECTIVES The objective of the study was to investigate the association between predialysis chronic kidney disease and contracting pneumonia in Taiwan. METHODS We employed a population-based, retrospective cohort design using the database of the Taiwan National Health Insurance (NHI) Program. There were 18807 subjects aged 20-84 years who were newly diagnosed with predialysis chronic kidney disease between 2000 to 2012 as the predialysis chronic kidney disease group and 18807 randomly selected subjects without chronic kidney disease as the non-chronic kidney disease group. The predialysis chronic kidney disease and non-chronic kidney disease groups were matched according to sex, age, comorbidities, and the year of index date. The incidence of contracting pneumonia among both groups at the end of 2013 was calculated. The multivariable Cox proportional hazards regression model was used to calculate the hazard ratio (HR) and 95% confidence interval (CI) for contracting pneumonia being associated with predialysis chronic kidney disease. RESULTS The overall incidence of contracting pneumonia was 1.47-fold higher in the predialysis chronic kidney disease group than that in the non-chronic kidney disease group (24.6 vs. 16.7 per 1, 000 person-years, 95% CI 1.40, 1.55). After adjusting for co-variables, the HR of contracting pneumonia became 1.52 for subjects with predialysis chronic kidney disease (95% CI 1.43, 1.60) compared to subjects without chronic kidney disease. With even further analysis, in the absence of any comorbidity, the adjusted HR of contracting pneumonia was 1.53 for subjects with predialysis chronic kidney disease alone (95% CI 1.32, 1.76). CONCLUSIONS Patients with predialysis chronic kidney disease have a 1.52-fold increased risk of contracting pneumonia as compared to those with non-chronic kidney disease. Even in the absence of any comorbidity, a greater than average risk of contracting pneumonia remains present.